Update: after the most recent security update I can now change the firewall exceptions. However the firewall is turned OFF by default (instructions from Microsoft tech). I remember that I disabled it from a startup list that I got to from the "Run" command line (as opposed to through security>firewall settings>turn firewall on/off etc). I don't remember the command that I used - I though it was mscsvc or similar, but I don't want to mess with commands that I don't know!
Thanks in advance